Exsanguination (colloquially known as bleeding out) is the fatal process of blood loss to an amount that causes death.
A typical cause of exsanguinations is traumatic injury where blood loss cannot be arrested. For example, exsanguination is the leading cause of death on a battlefield. Non-battlefield causes can include murder by shooting or stabbing; motor vehicle accidents; suicide by cutting arteries; and partial or complete amputation of limbs due to workplace accidents.
A victim does not have to lose all of his (her) blood to cause death. Depending upon the age, health, and fitness level of the individual, a victim may die from losing half or two-thirds of their blood. In battlefield situations, blood loss of an injured soldier may not be arrested to a sufficient degree during combat or in field hospitals, and blood loss to a fatal amount may occur during transport to a care center.
Auto-transfusion systems are known in the art, as evidenced, for example, by U.S. Pat. No. 6,951,553 to Bubb et al.; US 2009/0093754 to Hartig et al.; U.S. Pat. No. 5,078,677 to Gentelia et al.; U.S. Pat. No. 5,634,893 to Rishton; and U.S. Pat. No. 5,055,198 to Shettigar et al. Those systems, however, are bulky and not particularly suited for use in a battlefield, or in other emergency situations such as a fire rescue or an accident in a remote location where trained personnel or hospital equipment may not be readily available.
In those situations, application to the patient of a system in the prior art may be difficult; and air or dirt may become trapped within the system and be lethal to the patient; or blood recirculation may be defective, exposing the patient to the risk of oxygen deprivation and permanent damage.